What is CVE-2021-21724?

CVE-2021-21724 is a medium-severity vulnerability in ZTE Zxr10 8900e, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 4.4/10. Published 2021-02-26.

How severe is CVE-2021-21724?

Medium severity. CVSS v3 base score is 4.4 out of 10.

Vulnerability in ZTE Zxr10 8900e

CVE-2021-21724

A ZTE product has a memory leak vulnerability. Due to the product's improper handling of memory release in certain scenarios, a local attacker with device permissions repeatedly attenuated the optical signal to cause memory leak and abnormal service. This affects: ZXR10 8900E, all versions up to V3.03.20R2B30P1.

Published 2021-02-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.4 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (28.1th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000

Affected products

ZTE Zxr10 8900e
ZTE Zxr10 8900e Firmware
Zxr10 8900e — versions all versions up to V3.03.20R2B30P1

Weakness classification (CWE)

CWE-401 — Missing Release of Memory after Effective Lifetime

References

support.zte.com.cn/support/news/LoopholeInfoDetail.aspx (Vendor Advisory)

Frequently asked questions

What is CVE-2021-21724?: CVE-2021-21724 is a medium-severity vulnerability in ZTE Zxr10 8900e, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 4.4/10. Published 2021-02-26.
How severe is CVE-2021-21724?: Medium severity. CVSS v3 base score is 4.4 out of 10.